电工题,如图：R1=R2=10欧,R3=20欧,E1=4V,E2=2V.试用叠加原理求各支路电流.

很简单啦
1.设E2为零（电压源为零,相当于短路）,则E1产生的各支路电流为
I11 = E1/R = E1/(R1+R2//R3) = 4/(10+10//20) = 0.24A
R2//R3表示R2和R3并联
I21 = I11 * R3/(R2+R3) = 0.24*2/3 = 0.16A
I31 = I11 * R2/(R2+R3) = 0.24*1/3 = 0.08A
2.设E1为零,则E2产生的各支路电流为
I12 = E2/r = E2/(R2+R1//R3) = 2/(10+10//20) = 0.12A
I22 = I12 * R3/(R1+R3) = 0.12*2/3 = 0.08A
I32 = I12 * R2/(R1+R3) = 0.12*1/3 = 0.04A
3.根据叠加原理
I1 = I11+I12 = 0.36A
I2 = I21+I22 = 0.24A
I3 = I31+I32 = 0.12A